Manual flush valves for use in urinals, water closets, and toilets are well known in the art. Two common types of flush valves are diaphragm flush valves and piston flush valves. Diaphragm flush valves typically include a fluid inlet and a fluid outlet separated by a diaphragm that selectively prevents fluid from flowing from the fluid inlet to the fluid outlet. The diaphragm of a flush valve selectively prevents fluid from flowing from the fluid inlet to the fluid outlet by being disposed on a valve seat of the fluid outlet. The diaphragm of the flush valve includes a refill orifice that allows fluid flowing from the fluid inlet to flow into a top chamber above the diaphragm. Fluid in the top chamber above the diaphragm applies pressure to seat the diaphragm onto the valve seat of the fluid outlet. The diaphragm of the flush valve further includes a relief valve which selectively allows fluid to pass from the fluid inlet to the fluid outlet. The relief valve commonly features a valve stem that extends downward into the fluid outlet. The valve stem interfaces with a plunger connected to a manual lever arm. The manual lever arm is actuated by a user which pushes the plunger into contact with the valve stem. The contact of the plunger with the valve stem laterally displaces the valve stem which causes the relief valve to slightly open fluid communication between the fluid inlet and the fluid outlet. The slight opening in fluid communication caused by the displacement of the valve stem reduces pressure pressing the diaphragm onto the valve seat which allows the diaphragm to unseat from the valve seat. The unseating of the diaphragm from the valve seat allows additional fluid to flow from the fluid inlet to the fluid outlet. When the user releases the manual lever arm, the plunger returns to its original position. The valve stem returns to its original position when it is not being actuated by the plunger, and when the valve stem is in its original position, the relief valve is closed. Fluid pressure builds on the diaphragm with the relief valve closed. The increase in pressure on the diaphragm due to the closing of the relief valve presses the diaphragm onto the valve seat. Fluid communication between the inlet and the outlet is thereby closed with the diaphragm disposed on the valve seat and the relief valve closed.
Automated flush valves are also well known in the art. Automated flush valves commonly rely on sensors that detect the presence of a user in order to initiate a flush as opposed to a manual lever arm that requires actuation by a user. Automated flush valves have similar internal structures to manual flush valves. As noted with manual diaphragm flush valves, automated flush valves include a fluid inlet and a fluid outlet separated by a diaphragm that selectively prevents fluid from flowing from the fluid inlet to the fluid outlet. The diaphragm of the flush valve includes a refill orifice that allows fluid flowing from the fluid inlet to flow into a top chamber above the diaphragm. Fluid in the top chamber above the diaphragm applies pressure to seat the diaphragm onto the valve seat of the fluid outlet. The diaphragm of the flush valve selectively prevents fluid from flowing from the fluid inlet to the fluid outlet by being disposed on a valve seat of the fluid outlet. The diaphragm of a flush valve includes a relief valve which selectively allows fluid to pass from the fluid inlet to the fluid outlet. The relief valve commonly features a valve stem that extends downward into the fluid outlet. The valve stem interfaces with a plunger connected to an automated actuation mechanism. The automated actuation mechanism is configured to push the plunger into contact with the valve stem. The automated actuation mechanism most commonly utilizes a solenoid, while alternative embodiments can utilize a motor coupled to a gear train or other automated actuation mechanisms. The contact of the plunger with the valve stem laterally displaces the valve stem which causes the relief valve to slightly open fluid communication between the fluid inlet and the fluid outlet. The slight opening in fluid communication caused by the displacement of the valve stem reduces pressure pressing the diaphragm onto the valve seat which allows the diaphragm to unseat from the valve seat. The unseating of the diaphragm from the valve seat allows additional fluid to flow from the fluid inlet to the fluid outlet. When the automated actuation mechanism releases from contact with the plunger, the plunger returns to its original position. The valve stem returns to its original position when it is not being actuated by the plunger, and when the valve stem is in its original position, the relief valve is closed. Fluid pressure builds on the diaphragm with the relief valve closed. The increase in pressure on the diaphragm due to the closing of the relief valve presses the diaphragm onto the valve seat. Fluid communication between the inlet and the outlet is thereby closed with the diaphragm disposed on the valve seat and the relief valve closed.
The actuation of the valve stem by the plunger causes the valve stem to be at an angle with respect to the valve seat. The angle of the valve stem selectively opens the relief valve by tilting the relief valve at an angle relative to the valve seat. The selective opening of the relief valve is unpredictable due to variations in pressure applied to the diaphragm caused by fluid communicated into the upper chamber via the bypass opening in addition to the variation in the actuation by a user or an automated actuation mechanism. The unpredictability of the opening causes control and precision problems. The amount of fluid flowing through the opening is correlated to the size of the opening in the relief valve. The amount of fluid flowing through the flush valve is difficult to control due to the unpredictability of the opening in the relief valve. The timing of a flush cycle is also correlated to the size of the opening allowing water to pass through the relief valve. The unpredictability of the opening in the relief valve also makes the timing of a flush cycle difficult to control.
Additional disadvantages arise with commonly utilized solenoids for automated actuation of the plunger. First, solenoids and their components tend to corrode in the presence of hard water. Second, solenoids exhibit inconsistent performance at varying pressures that may cause the plunger to bounce in response to a high or a low pressure. Third, solenoids have an increased sensitivity to manufacturing tolerances (e.g. spring forces, magnetic force, etc.). Each of these disadvantages, alone or in combination with one another, may cause undesirable performance and maintenance issues.
It is therefore desirable for a flush valve to more precisely control the opening in the relief valve and improve durability of the components in the flush valve.